Use the Hinge Interaction Surface form as follows:
Select one of the available options:
Default from Material Property of Associate Frame Object. As the name suggests, the interaction surface is derived based on the material property definition assigned to the frame object to which the hinge is assigned.
Steel, AISC-LRFD Equations H1-1a and H1-1b with phi = 1. Type in the expected yield strength in the appropriate Expected Yield Strength edit box.
Steel, ASCE 41-13 Equation 9-4. Type in the expected yield strength in the appropriate Expected Yield Strength edit box.
Concrete, ACI 318-02 with phi = 1. The methodology used for developing the interaction surface using the "Concrete, ACI 318-02 with phi = 1" option is the same as that documented in the Concrete Design Manual, with the following exceptions:
The phi factor is set equal to 1.
The maximum compressive axial load is not limited to Pmax.
For the pushover interaction surface, axial tension is positive, and axial compression is negative. This is an opposite sign convention from that used in concrete design, but it is consistent with analysis results.
Refer to ACI 318-02 for additional information.
User Definition.
When the Doubly Symmetric About M2 and M3 check box is checked (which it is by default), input the interaction surface in the (+M2, +M3) quadrant for all values of P (i.e., both positive and negative) in the spreadsheet of the Interaction Surface Definition form (which displays by clicking the Define/Show Surface button). Thus only 90 degrees of the full 360-degree interaction surface is input. Symmetry is used by the program to define the interaction surface in the (–M2, +M3), (–M2, –M3), and (+M2, –M3) quadrants. If the Doubly Symmetric About M2 and M3 check box is unchecked, all 360 degrees of the interaction surface must be input.
The Number of Curves edit box indicates the number of equally spaced P-M curves that will be used to define the interaction surface ( 5 curves is the default). If the Doubly Symmetric About M2 and M3 check box is checked, the curves are equally spaced between 0 and 90 degrees. If the Doubly Symmetric About M2 and M3 box is unchecked, the curves are equally spaced between 0 and 360 degrees.
Click the Define/Show User Interaction Surface button to open the {Curve} Interaction Surface Definition for {Property Name} form and define or view the interaction surface curves.
Axial Load - Displacement Relationships options. This area of the form is available when the hinge type is Interacting P-M2-M3, P-M2, or P-M3. Select the axial behavior:
Choose Proportional to Moment-Rotation for an axial load-deformation relationship that hardens and softens according to the shape of the given M3/M3SF versus q3/q3SF plot.
Choose Elastic - Perfectly Plastic for an independent axial load-deformation relationship based on the maximum and minimum axial yield values from the interaction surface.
Axial Force - When the curve is an Interacting M2-M3, specify the P associated with the M2-M3 curve with positive tension.
Access the Hinge Interaction Surface form as follows:
Click the Define menu > Section Properties > Frame/Wall Nonlinear Hinge command to access the Define Frame/Wall Hinge Properties form. Then do one of the following:
Click the Add New Property button. The Default For Added Hinges form, with Steel, Concrete, and User Define options, will display. Choose an option as the basis for defining the new hinge property. The Hinge Property Data form will display.
Highlight a previously defined property and click the Add Copy of Property or Modify/Show Property button. The Hinge Property Data form will display.
Ensure that the Force Controlled (Brittle) option has been selected and that an Interacting hinge type (P-M2, PM-3, P-M2-M3) has been selected from the drop-down list of hinge types.
Click the Modify/Show Hinge Property button to access the Hinge Property Data for {Hinge ID - Interacting [Hinge Type]} form.
Click the Modify/Show {P-M2, PM-3, PMM} Interaction Surface (Capacity) Data button.